\u81ea\u589e\u4e3b\u952e\u6ca1\u6709\u6301\u4e45\u5316\u662f\u4e2a\u6bd4\u8f83\u65e9\u7684bug\uff0c\u8fd9\u70b9\u4ece\u5176\u5728\u5b98\u65b9bug\u7f51\u7ad9\u7684id\u53f7\u4e5f\u53ef\u770b\u51fa\uff08https:\/\/bugs.mysql.com\/bug.php?id=199\uff09\u3002\u7531Peter Zaitsev\uff08\u73b0Percona CEO\uff09\u4e8e2003\u5e74\u63d0\u51fa\u3002\u5386\u53f2\u60a0\u4e45\u4e14\u81ed\u540d\u662d\u8457\u3002<\/p>\n
\u9996\u5148\uff0c\u76f4\u89c2\u7684\u91cd\u73b0\u4e0b\u3002<\/p>\n
mysql> create table t1(id int auto_increment primary key);
\nQuery OK, 0 rows affected (0.01 sec)<\/p>\n
mysql> insert into t1 values(null),(null),(null);
\nQuery OK, 3 rows affected (0.01 sec)
\nRecords: 3\u00a0 Duplicates: 0\u00a0 Warnings: 0<\/p>\n
mysql> select * from t1;
\n+—-+
\n| id |
\n+—-+
\n|\u00a0 1 |
\n|\u00a0 2 |
\n|\u00a0 3 |
\n+—-+
\n3 rows in set (0.00 sec)<\/p>\n
mysql> delete from t1 where id=3;
\nQuery OK, 1 row affected (0.36 sec)<\/p>\n
mysql> insert into t1 values(null);
\nQuery OK, 1 row affected (0.35 sec)<\/p>\n
mysql> select * from t1;
\n+—-+
\n| id |
\n+—-+
\n|\u00a0 1 |
\n|\u00a0 2 |
\n|\u00a0 4 |
\n+—-+
\n3 rows in set (0.01 sec)<\/p>\n
\u867d\u7136id\u4e3a3\u7684\u8bb0\u5f55\u5220\u9664\u4e86\uff0c\u4f46\u518d\u6b21\u63d2\u5165null\u503c\u65f6\uff0c\u5e76\u6ca1\u6709\u91cd\u7528\u88ab\u5220\u9664\u76843\uff0c\u800c\u662f\u5206\u914d\u4e864\u3002<\/p>\n
\u5220\u9664id\u4e3a4\u7684\u8bb0\u5f55\uff0c\u91cd\u542f\u6570\u636e\u5e93\uff0c\u91cd\u65b0\u63d2\u5165\u4e00\u4e2anull\u503c\u3002<\/p>\n
mysql> delete from t1 where id=4;
\n# service mysqld restart
\nmysql> insert into t1 values(null);
\nQuery OK, 1 row affected (0.00 sec)<\/p>\n
mysql> select * from t1;
\n+—-+
\n| id |
\n+—-+
\n|\u00a0 1 |
\n|\u00a0 2 |
\n|\u00a0 3 |
\n+—-+
\n3 rows in set (0.00 sec)<\/p>\n
\u53ef\u4ee5\u770b\u5230\uff0c\u65b0\u63d2\u5165\u7684null\u503c\u5206\u914d\u7684\u662f3\uff0c\u6309\u7167\u91cd\u542f\u524d\u7684\u64cd\u4f5c\u903b\u8f91\uff0c\u6b64\u5904\u5e94\u8be5\u5206\u914d5\u554a\u3002<\/p>\n
\u8fd9\u5c31\u662f\u81ea\u589e\u4e3b\u952e\u6ca1\u6709\u6301\u4e45\u5316\u7684bug\u3002\u7a76\u5176\u539f\u56e0\uff0c\u5728\u4e8e\u81ea\u589e\u4e3b\u952e\u7684\u5206\u914d\uff0c\u662f\u7531InnoDB\u6570\u636e\u5b57\u5178\u5185\u90e8\u4e00\u4e2a\u8ba1\u6570\u5668\u6765\u51b3\u5b9a\u7684\uff0c\u800c\u8be5\u8ba1\u6570\u5668\u53ea\u5728\u5185\u5b58\u4e2d\u7ef4\u62a4\uff0c\u5e76\u4e0d\u4f1a\u6301\u4e45\u5316\u5230\u78c1\u76d8\u4e2d\u3002\u5f53\u6570\u636e\u5e93\u91cd\u542f\u65f6\uff0c\u8be5\u8ba1\u6570\u5668\u4f1a\u901a\u8fc7\u4e0b\u9762\u8fd9\u79cd\u65b9\u5f0f\u521d\u59cb\u5316\u3002<\/p>\n
SELECT MAX(ai_col) FROM table_name FOR UPDATE;<\/p>\n
MySQL 8.0\u7684\u89e3\u51b3\u601d\u8def<\/p>\n
\u5c06\u81ea\u589e\u4e3b\u952e\u7684\u8ba1\u6570\u5668\u6301\u4e45\u5316\u5230redo log\u4e2d\u3002\u6bcf\u6b21\u8ba1\u6570\u5668\u53d1\u751f\u6539\u53d8\uff0c\u90fd\u4f1a\u5c06\u5176\u5199\u5165\u5230redo log\u4e2d\u3002\u5982\u679c\u6570\u636e\u5e93\u53d1\u751f\u91cd\u542f\uff0cInnoDB\u4f1a\u6839\u636eredo log\u4e2d\u7684\u8ba1\u6570\u5668\u4fe1\u606f\u6765\u521d\u59cb\u5316\u5176\u5185\u5b58\u503c\u3002\u4e3a\u4e86\u5c3d\u91cf\u51cf\u5c0f\u5bf9\u7cfb\u7edf\u6027\u80fd\u7684\u5f71\u54cd\uff0c\u8ba1\u6570\u5668\u5199\u5165\u5230redo log\u4e2d\uff0c\u5e76\u4e0d\u4f1a\u9a6c\u4e0a\u5237\u65b0\u3002\u5177\u4f53\u53ef\u53c2\u8003\uff1ahttps:\/\/dev.mysql.com\/worklog\/task\/?id=6204<\/p>\n
\u56e0\u81ea\u589e\u4e3b\u952e\u6ca1\u6709\u6301\u4e45\u5316\u800c\u51fa\u73b0\u95ee\u9898\u7684\u5e38\u89c1\u573a\u666f\uff1a<\/p>\n
1. \u4e1a\u52a1\u5c06\u81ea\u589e\u4e3b\u952e\u4f5c\u4e3a\u4e1a\u52a1\u4e3b\u952e\uff0c\u540c\u65f6\uff0c\u4e1a\u52a1\u4e0a\u53c8\u8981\u6c42\u4e3b\u952e\u4e0d\u80fd\u91cd\u590d\u3002<\/p>\n
2. \u6570\u636e\u4f1a\u88ab\u5f52\u6863\u3002\u5728\u5f52\u6863\u7684\u8fc7\u7a0b\u4e2d\u6709\u53ef\u80fd\u4f1a\u4ea7\u751f\u4e3b\u952e\u51b2\u7a81\u3002<\/p>\n
\u6240\u4ee5\uff0c\u5f3a\u70c8\u5efa\u8bae\u4e0d\u8981\u4f7f\u7528\u81ea\u589e\u4e3b\u952e\u4f5c\u4e3a\u4e1a\u52a1\u4e3b\u952e\u3002\u5228\u9664\u8fd9\u4e24\u4e2a\u573a\u666f\uff0c\u5176\u5b9e\uff0c\u81ea\u589e\u4e3b\u952e\u6ca1\u6709\u6301\u4e45\u5316\u7684\u95ee\u9898\u5e76\u4e0d\u662f\u5f88\u5927\uff0c\u8fdc\u6ca1\u6709\u60f3\u8c61\u4e2d\u7684\u201d\u81ed\u540d\u662d\u8457\u201c\u3002<\/p>\n
\u6700\u540e\uff0c\u7ed9\u51fa\u4e00\u4e2a\u5f52\u6863\u573a\u666f\u4e0b\u7684\u89e3\u51b3\u65b9\u6848\uff0c<\/p>\n
\u521b\u5efa\u4e00\u4e2a\u5b58\u50a8\u8fc7\u7a0b\uff0c\u6839\u636etable2\uff08\u5f52\u6863\u8868\uff09\u81ea\u589e\u4e3b\u952e\u7684\u6700\u5927\u503c\u6765\u521d\u59cb\u5316table1\uff08\u5728\u7ebf\u8868\uff09\u3002\u8fd9\u4e2a\u5b58\u50a8\u8fc7\u7a0b\u53ef\u653e\u5230init_file\u53c2\u6570\u6307\u5b9a\u7684\u6587\u4ef6\u4e2d\uff0c\u8be5\u6587\u4ef6\u4e2d\u7684SQL\u4f1a\u5728\u6570\u636e\u5e93\u542f\u52a8\u65f6\u6267\u884c\u3002<\/p>\n
DELIMITER ;;
\nCREATE PROCEDURE `auto_increment_fromtable2`(IN table1 VARCHAR(255), IN table2 VARCHAR(255))
\nBEGIN
\nset @qry = concat(‘SELECT @max1 := (`id` + 1) FROM `’,table1,’` ORDER BY `id` DESC LIMIT 1;’);
\nprepare stmt from @qry;
\nexecute stmt;
\ndeallocate prepare stmt;
\nset @qry = concat(‘SELECT @max2 := (`id` + 1) FROM `’,table2,’` ORDER BY `id` DESC LIMIT 1;’);
\nprepare stmt from @qry;
\nexecute stmt;
\ndeallocate prepare stmt;
\nIF @max1 < @max2 THEN
\nset @qry = concat(‘alter table `’,table1,’` auto_increment=’,@max2);prepare stmt from @qry;execute stmt;deallocate prepare stmt;
\nSELECT ‘updated’ as `status`;
\nelse
\nSELECT ‘no update needed’ as `status`;
\nEND IF;
\nEND ;;
\nDELIMITER ;<\/p>\n","protected":false},"excerpt":{"rendered":"
\u81ea\u589e\u4e3b\u952e\u6ca1\u6709\u6301\u4e45\u5316\u662f\u4e2a\u6bd4\u8f83\u65e9\u7684bug\uff0c\u8fd9\u70b9\u4ece\u5176\u5728\u5b98\u65b9bug\u7f51\u7ad9\u7684id\u53f7\u4e5f\u53ef\u770b\u51fa\uff08https:\/\/bugs.my … \u9605\u8bfb\u66f4\u591a<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[10],"tags":[840],"class_list":["post-3485","post","type-post","status-publish","format-standard","hentry","category-shujuku","tag-mysql-8"],"aioseo_notices":[],"jetpack_featured_media_url":"","jetpack-related-posts":[],"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/posts\/3485","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/comments?post=3485"}],"version-history":[{"count":1,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/posts\/3485\/revisions"}],"predecessor-version":[{"id":3486,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/posts\/3485\/revisions\/3486"}],"wp:attachment":[{"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/media?parent=3485"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/categories?post=3485"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/cn.hostease.com\/xueyuan\/wp-json\/wp\/v2\/tags?post=3485"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}